Electric switch



Sept. 8, 1.942. A.)E. BAAK 2,295,151K

ELECTRIC SWITCH Filed March 29, 1940 i Ameri" E. :aux y Parental sept. s, 1942 Albert E. Baak. Minneapolis, Minn., assigner to minneapolis-Honeywell Regulator Company,

I I Minneapolis Minn., a corporation oi' Delaware' Application mmh ze, 1940, serum. szersczVQ s claims. (c1. zoo-a7) The present invention relates to electric switches and is concerned more particularly with a switch employing mechanical means to obtain a snap action.

An object of the invention is t0 provide novel means to obtain a snap action in an electric switch.

Another object is to provide a mechanically operated electric switch in which a single spring is elective` both to cause the contacts to be moved with a s nap action and to provide a self return of the switch tol aninitial condition.

Other objects will be apparent from the draw-v ing, specication, and claims. Y

In the. drawing:

Figure 1 is a view of onev sideof the switch showing the cover in place but in section to v disclose the internal mechanism,

Figure 2 is arvievv of the top of the switch with the cover removed, and

Figure a is. a view of the side of the svritch l opposite to the side shown in Figure 1.

Figure .4 is a partial'view similar to Figure 2 with certain parts removed.

The switch which is shown in diierent views in the four gures of the drawing comprises a `base I0 moulded of suitable insulating material.

0n one end of the base 'and formed integral therewith is an upstanding contact carrying portion Il. Likewise, on the opposite end of the base is a second upstanding contact ca portion l2. A resilent contact blade Il extends longitudinally of the switch from the top of the upstanding portion Il of the base I0 and is secured thereto by a screw l5 which screws into a tion 29 extendingbeyond contact 21 and bent downwardly to frictionally engage the base l0 for the purpose of damping out any vibration set up in the contact blades as contact 2S is snapped into engagement with contact 21.

I provide a novel snap action mechanism for operating the contacts above described. A supportll is suitably secured to the base I9 as by rivets (not shown) vand is stamped from a. single sheet of metal. As best shown in Figure 1, -the support includes three pairs of upstanding ear portions 32, 33,and 3Iwhlch serve purposes as will be hereinafter pointed out. 'I'he right-hand edges of ear portions 33 as shown in Figure 1 are so formed as to provide V-shaped notches* i 31 which serve to pivot a leaf 'spring 38 which isV provided with a second abutment in the form of a screw 39 which may be adjusted through the vbottom ofvbase Il to vary the tension of the spring 38. The right-hand end of spring 38 as seen in Figure 1 is bent upwardly in the form of a pair o i ear portions Il.'

' y ing lever I3 having an opening M through its suitable metal sleeve l1 embeddedin the pori tion Il of the bese and extending verticallyV therethroughtothebottomof the base Il where aterminalscrew It enables anexternalelectrlcal'connectinn tube-made tothe contact blade IdkeWImtotheupstandingportionlatthe othrend'ofthemell'issecuredacontnct bladeIlbymeansofascrewlwhichissecuredintoamemsleeveembedded'inthe portionllofbasell. Likethesleevellin theotherendofthemthissleeve'extmds.

verticallytherethroughsothatanexternalelectricalconnectionmnbemadetohladellby meansodatcrnrlmlscrewll. Contacthlade Ilismlntantldlymhtandhasmountedon thelettinndaldthereofasseeningmuz andSamitnhlecnntnctbuttonIlpxeferably ofsilvcr. Admihreoopentlngeontlctll mountcdonbladell. 'Ihebladellhnsapcr-SE standing center is pivoted at its right-hand' end (Figure 1) in the ear portions 4I extending upwardly from spring 3l. The ear portions 4|. extend through a pair of slots 41 ln actuating lever 43, as best seen in Figure 2. This end of lever 43 is bent upwardly in order to form a knife edge contact with ear portions 4I thereby reducingv friction. 'I'he opposite end of lever I3 ismovv able between stops 45 and formed yin the upstandlng-ear portionsl! ofl the supporting member 3|.' As best seen in Figure 2 lever 43 has a portion 4I extending under contact blade Il for separating the contacts when the mechanismis actuatedsothattheleverisagainst theupperstopll. A

A linx member is pivoted in lever n in o knife edge contact in the righthand end of theopeningllandextendsgenerallyparallelto leverbutisadaptedtobeactuatedovercenter withrespectthereto. Theoppoteendoflink Ilispivotedinaknife'edgecontacttoanoperatingleverlwhichintumispivctedbymeans otaknileedgecontactmthetwoupstanding earportlomllofsupportu. Thetwo'hiifeporiionsof properhtenlnlignmen portinnsotsupportilwhichtorm A contact actuatmiddle.

applied to the. switch,the parte the position shown.

the pivots :1 for spring n is-siso formed'to provide stops 54 andi to limit movement of the operating lever 52. by engaging a pair of best seen in Figure 4.

direction will therefore cause the left-hand end of the contact actuatingv lever 43 as seen in Fig- :twin be noted in r'igune 4 that the contact actuating lever 43 and the leaf spring 38 includving the upstanding ear portions 4i have been removed to show more clearly the operating lever "32 and the ears i2 thereon in their relation to the ear portions 33 and 34 which extend upwardly from the support 3l.

The upper stops I4 of the ear portions 33 of the support 3i serve to prevent clockwise moveand 21. It is not necessary that lever l2 be moved further in a counter-clockwise direction once this snap action is instigated because clockwise snap of lever 43 from the lower stop various parts in their proper 'position when there lo 'is no force applied to the lever 52 tending to at a point between'the two pairs of `stops i4 and 5I. 'I'he operation of my switch is as follows: -with the various parts of the switch in the position -shown in the drawing,v an initial tension exists in the springv 38. This tension is adjustable by mears of the screw 39 to bow the spring 38 so that it takes'a slight downward curve in the The upstanding ear portions 4I of spring' 38 are therefore exerting a force encon-` tact actuating lever 43 tending to move it to the right as seen in Figure A1. Such 'movement is prevented by the operating lever 32 and the link 50. Counter-clockwise rotation of actuating lever 43 is preventedby the stops. in the ear portions 32 while endwise movement is prevented bythe link ,50. The link I3 is prevented from moving endwise by the operating lever 52 which abuts the ears 34 at its pivot therein and Yis prevented from rotating clockwise (as in Figure 1) by the stops I4 in the ears 33. Il no vdownward force is applied to the operating lever` l2. it will assume its uppermost position because -thestops 55 in the ears 33 preventalignment of the pivots of the link 53 and the lever 3 2. Sincethese pivots. are never aligned, the spring 33 biasing the actuating lever 43 to the right Vwill continually tend to collapse the toggle joint formed by the link 83 and the operating lever 32. Thus the link 53 will be pivoted in the lever 45 tothe upper stop 43. The lower stop Il in ear portions 33 of support 3i is eifective therefore to prevent excessi counter-clockwise movement of the lever 52 by the push button 33 and prevent augment of the pivot points of the toggle joint formed by lever 52 and link I8. Be-

cause these pivots never become aligned. Spring 38 will always be supplying the force tending and linkin. Therefore when the downward force on push button 60 is removed the .above mentioned togglev joint will collapse which will raise the pivot between 'lever i2 and `link ll luntil it again becomes aligned with the pivots at the two opposite ends of the contact actuati ing lever 43. When'A this occurs the left-hand end of lever 43 which has been in contact with the upper stop 48 of the upstanding earportion 3 3 of support 3i will move downwardlywith -a snap action to again closethe contacts.

It will therefore be seen that the spring 33 serves to cause operation of the contact actuat- Ving lever 43 between stops 43 and 40 with a snap Y action as is 'customary in overcenter' snap switches: However, by reason of the pivot for the lever 82 in ear portions 34 being out oi' line with the other pivots ofthe mechanism during all phases of operation, spring 38 is also able to` Supply the force necessary to return the mechanism to its initial position. In tracing the action of the spring through the various opera'- x j tions it will be seen that its tension is increased when push button 68 is depressed until the snap action occurs which opens the contacts. -During this snap action spring 38 gives up a small amount of its. tension to open the contacts.- As

push button 80 is raised the spring tension dey 32 at a point above the actuating lever 43 and will consequently bias the lever 43 against the lower pair of stops 45. The stops '43 and Il and the. pivot of the lever 32 in the ears 34 are'so disposed thatthe lever 52 is also biased upwardly by the spring 38 when the lever 32 is in its lowermost position. Hence, when no external force is will always bein When a downward force is applied to push button 80, operatingv lever i2 is caused to rotate counter-clockwise about its pivot in the ear portions 34. When the pivot of the lever 82 in the link 53 becomes aligned with the pivots at the two ends of contact actuating lever 43, a dead center condition willA exist. Further the contacts. Then during this snap action the spring tension is reduced to its lowest or initial value.

f It win'tiierefore be seei'i that r have provided a novelsnap acting electrical switch in which a singlespring servesboth to cause the snap action and to return the mechanism toits initial position. While one form .of the invention has been illustrated and described it is `evident that numerous modifications could vbe made without departing from the spirit of the invention and thereforelwishtobelimitedonlybytheappended claims.

I claim as my invention: i Y 1. In an electrical switching mechanism. in combination, a support, a pivoted contact actuating. lever, a pair of stops for limiting rota# said toggleiiointthe pivot 'for ssid second linx movement of lever 52' in. va counter-clockwise'75 in said support being located o ut of line with respect to the pivots for said contact actuating lever and for said first link in s aid actuating leverv so that as said tossle is` moved toward aligned position, the center pivot of the toggle will be moved over center with respect to the -pivot for said lever and the pivot for said toggle joint in said lever without alignment of the pivot points of the toggle joint.

2. In an electrical switching mechanism, in

combination, a support, a pair of mating contacts, an actuating member pivoted with respect l to said support for moving one of the contacts,

means carried by said support to limit rotational movement of the actuating member about its pivot, a toggle joint pivoted at one end in the actuating member and pivoted at the other end in said support at a point so located that the center pivot of the toggle can pass over center with respect to the pivot for the actuating member and the pivot of the toggle joint in the actuating member without the pivots of the having a rst rigid link pivoted in said lever and a second rigid link pivoted in said support, and

a spring carried by said support and acting on said lever tending to collapse said toggle joint,

the pivot for said second link in said support besaid toggle joint in said lever without alignment of the pivot points of the toggle joint.

6. In an electrical switching mechanism, in combination, a support, a contact actuating lever resiliently pivoted in said support so as to be Y biased longitudinally with respect thereto, means toggle joint becoming aligned, and a spring acting on the pivot for said actuating member to place the two links of the toggle joint in compression.

3. In an electrical switching mechanism, in combination, a leaf spring, a pivot carried by said spring, a pair of abutments forsaid spring, a contact actuating lever carried in the pivot that is carried by said spring, a pair of stops ,lor limiting movement of said contact actuating lever about its pivot; a link pivoted in said lever to oppose by compression the force of said spring on said contact actuating lever, a second pivot for said link movable over center with respect to the pivots in said contact actuating lever, a second lever pivoted at one end in said second pivot for said link and at the other end at a point out of line with the dead center of said mechanism, and means for actuating said second lever.

4. In an electrical switching mechanism, in combination, a support, a pivoted contact actuating lever, a pair of stops for limiting rotational movement of said lever, a toggle joint having `a rst rigid link pivoted in said lever and a second rigid link pivoted in said support, a spring carried by said support and acting on said lever tending to collapse said toggle joint, a stop limiting the amount of collapse .of said toggle joint,

.the pivot for said second link in said support being located .out of line with respect to the pivots for said contactactuating lever and for said iirst link in said actuatig lever so that as said toggle is moved toward alignedpositon, the center pivot of the toggle will be moved over center with respect to the pivot for said lever and the pivot for said toggle joint in said lever without alignment of the pivot points of the toggle joint, and means associated with said support for adjusting the force of said spring.

5. In an electrical switching mechanism, inA

combination, a. support. a pivoted contact actuating lever, a pair oi' stops for limiting rotational movement ofvsaid lever, a toggle joint for limiting rotational movement of'said actuating lever with respect to said support, a toggle joint having a rst rigid link pivoted in said lever and a second rigid link pivoted in said support,

the axis of the pivot for'said togglev joint in said support lying outside a plane passed through the ,axes of the pivots of said actuating lever in said support and of said toggle joint in said actuating lever at all positions of said actuating lever.

V'1. In an electrical switching mechanism, .in combination, a support, a contact actuating lever, a pivot for said actuating lever carried by said support, means for limiting rotational movement of said actuating lever with respect to said support. a toggle joint having a rst rigid link pivoted in said lever` and a second rigid link pivoted with respect to said Isupport, a pivot for said second link carried by said support, the axis of said pivot for said toggle joint lying outside a plane passed through the aires of said pivot for said actuating lever and the pivot for said toggle joint in said lever at all positions of said actu- .ating lever, and spring means carried by said support and acting on one of saidpivots for placing said actuating lever-in tension.

8. In an electrical switching mechanism,v in

combination, a support, a contact actuating lever, a pivot for said actuating lever carried by said support, means for limiting rotational movement of said actuating lever with respect to said support, a toggle joint having a rst rigid link lpivoted in said lever and a second rigid'link pivoted with respect to said support, a. pivot for said second link carried by said support, the axis of said pivot for said toggle joint lying outside a plane passed through the axes of said pivot for said actuating lever and the pivot for said toggle joint in said lever at all positions of ysaid actuating lever, spring means carried by'said support and acting on one of said pivots for`placing said actuating lever in tension, and means associated with said support for-adjusting the force of said spring means.

ALBERT E. BAAK. 

